Orthopedic implant surface configuration with a projection having a back cut

ABSTRACT

The present invention is a specialized orthopedic implant having an exterior surface for engaging bone. The surface comprises arrayed projections having at least one forward facing facet directed at least in part toward the leading end of the implant and at least one rearward portion directed at least in part toward the opposite trailing end of the implant. Each of the forward facet and rearward portion has a length and a slope. The length of the forward facet is longer than the length of the rearward facet. The slope of the rearward facet is steeper than the slope of the forward facet. The surface projections also have opposed side facets directed generally toward the sides of the implant. The side facets are located between the forward facet and rearward facet and converge toward each other in a direction away from the base of the surface projections. The surface may also include projections having left and right forward side facets and a rearward facet. The surface further may include projections having left and right rearward side facets and a forward facet.

RELATED APPLICATION

This application is a divisional of application Ser. No. 09/572,518,filed May 17, 2000 now U.S. Pat. No. 7,115,143; which is acontinuation-in-part of application Ser. No. 09/457,228, filed Dec. 8,1999 now U.S. Pat. No. 6,287,740; all of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION Description of the Related Art

The present invention relates to orthopedic implants for placement atleast in part into bone, or for placement at least in part betweenadjacent bones or bone portions of a human skeleton. The orthopedicimplants of the present invention have a specialized surface forengaging bone.

Vital to the functioning of such orthopedic implants is their ability toremain properly located within bone after installation. In U.S. Pat.Nos. 5,593,409 and 5,609,635, Michelson described the use of surfaceroughenings, such as knurling or ratcheting on the opposed upper andlower vertebral body engaging surfaces of interbody spinal fusionimplants. Knurling has been particularly beneficial for increasing thegrip of the implant surface to the bone of the adjacent vertebral bodiesin a rather uniform manner without a directional bias. Orthopedicimplants inserted at least in part into bone, have a propensity to movein a particular direction, which is opposite to their path of insertion,because this is the path of least resistance. Such propensity to move isfurther increased when the implant has an overall configuration that istapered along at least a portion of its length such that the boneengaging surfaces of the implant are in angular relationship to eachotherand are spaced further apart at the implant's trailing end than atthe implant's leading end. In such circumstances where it is desirablethen to gain stability in resistance to a particular direction ofmovement of the orthopedic implant, the use of a plurality of forwardfacing ratchetings on the implant's bone engaging surfaces has beenpreferable to the previously described knurling for that purpose.

The term “ratcheting” as used herein is defined as a plurality ofangular teeth or ridges or protrusions projecting from the surface of animplant to resist motion of the implant at least in one direction. Thephrase “forward facing ratchetings” as used herein is defined as aratcheting having at least one forward facing facet having a lengthgreater than a rearward facing facet and an angle from the implantsurface from which the forward facing facet arises that is less steepthan the angle of the rearward facet. On an implant surface, forwardfacing ratchetings facilitate the insertion of the implant in onedirection and after insertion, resisting movement of the implant in adirection opposite to the direction of insertion. An example of forwardfacing ratchetings of the prior art is shown in partial fragmentary viewin FIGS. 24A and 24B, generally referred to by the reference numeral 50.

Knurled surfaces of the related art provide some stability in alldirections, but lack the ability to resist a particular direction ofmotion preferentially. The above-described ratcheted surface bestresists motion in a particular direction. There exists a need for animproved orthopedic implant surface configuration, wherein the boneengaging surfaces of the implant are configured to be resistant toimplant movement in all directions, and preferentially in particularlyone direction.

SUMMARY OF THE INVENTION

The present invention relates to orthopedic implants having aspecialized surface configuration on at least a portion of the exteriorsurfaces adapted for engaging bone, including adjacent bones and boneportions, into which the implant is to be implanted. Such an implantsurface configuration has utility with a wide variety of shapes oforthopedic implants where enhanced skeletal fixation is desired. Such animplant surface configuration can provide for enhanced stability,increased surface area, and a surface for the delivery of fusionpromoting substances other than bone. In a preferred embodiment, theimplant surface can provide for resisting motion in all directions, andparticularly in at least one direction, such as counter to the directionof insertion of the implant.

While various embodiments of the present invention are presented by wayof example only and not limitation, common to each of them is that thesurface configuration incorporates a plurality of spatially integratedsurface projections having at least one forward facing facet directed atleast in part toward the leading end of the implant and at least onerearward portion directed at least in part toward the opposite trailingend of the implant. By way of example and not limitation, the rearwardportion may be a facet, a line, or an edge of the rearward aspect of thesurface projection formed where two facets come together. Each of theforward and rearward facets have a length and a slope. The length of theforward facet is longer than the length of the rearward facet. The slopeof the rearward facet is steeper than the slope of the forward facet. Invarious embodiments, the surface projections also have opposed sidefacets directed generally toward the sides of the implant. The sidefacets are located between the forward facet and rearward facet and mayconverge toward each other in a direction away from the base of thesurface projections. The surface comprises multifaceted ratchetedprojections that are organized in geometrically disposed fields orarrays which are at a minimum located on at least a portion of the boneengaging surfaces of the implant. From the teachings disclosed herein,it is appreciated that the surface projections can be geometricallyarranged in a pattern wherein at least a portion of the projection isaligned along a longitudinal, horizontal, diagonal, or curved line. Thebone engaging surfaces of the implant can be at least in part arcuate orplanar and can converge along a portion or all of the length of theimplant.

In various preferred embodiments of the present invention, the rearwardfacets of the surface projections can be perpendicular or at anglesgreater or less than 90 degrees to exterior surface of the implant fromwhich the projections arise. The opposed side facets of the surfaceprojections can have at least a first portion in a plane at an angle tothe longitudinal axis of the implant. The opposed side facets canintersect each other, and can converge to form a peak at the top of eachof the surface projections. The peaks can be aligned along lines thatare perpendicular, parallel, or diagonal to the longitudinal axis of theimplant. The surface projections can be cleaved such as by longitudinaland/or horizontal cuts to increase the number of exposed sides of theprojections and thus increase the available surface area to contact andengage the bone adjacent the implant and increase the number of recessedareas to contain material such as fusion promoting substances forexample. Alternatively, the peaks of each surface projection can becleaved, truncated, or flattened at least in part.

The surface projections can include a left forward side facet and aright forward side facet directed toward the leading end and sides,respectively, of the implant. Similarly, the surface projections caninclude a left rearward side facet and a right rearward side facetdirected toward the trailing end and sides, respectively, of theimplant. The side facets of adjacent surface projections can be spacedapart to define a groove therebetween. A plurality of adjacent surfaceprojections can be spaced apart to form a plurality of grooves that canbe parallel or at an angle to the longitudinal axis of the implant,wherein the angle can be less than 90 degrees. The grooves can have ahorizontal cross section that is a V-shape, U-shape, or a box-likeshape, for example.

Sequential projections can be positioned on an implant wherein eachsurface projection has forward facing facets facing the same direction,such that consecutive projections are oriented forward facing facet torearward facing facet. The lower most portion of the slope of theforward facing facet of a first surface projection in a sequence can becoincident with the rearward facet of the next surface projection in thesequence. Alternatively, the forward facet of a first surface projectionand the rearward facet of the next surface projection in a sequence canbe spaced apart and the space can be at least in part flat, curved, orany other surface contour suitable for the intended use. The surfaceprojections can be oriented relative to one another to form fields orarrays that further can be geometrically disposed relative to oneanother, preferably in a pattern wherein at least a portion of theprojection is aligned along a longitudinal, horizontal, diagonal, orcurved line.

The surface configuration of the present invention can be formed bycasting, machining, or any other techniques known to one of ordinaryskill in the art. The present surface configuration may readily bemachined by milling the implant surface from side to side, across thebone engaging surfaces, to form ratchetings generally disposedperpendicular to the long axis of the implant and generally formedfacing to the insertion end of the implant. The ratchetings may be crossmachined with an angled cutting face to form grooves passing through theratchetings. For example, a milling machine having a cutting tool, witha V-shaped profile, can be run through the plurality of ratchetingsparallel to the longitudinal axis of the implant to form theabove-described surface. In a preferred embodiment, the V-shaped cuttingtool of the milling machine has opposed cutting faces with an angle ofapproximately 90 degrees to each other, which faces are each at a45-degree angle to the plane of the surfaces being machined. Withoutdeparting from the scope of the present invention, the angle of thecutting faces can be more or less than 90 degrees, and the angle of thecutting face to the surface to be cut can be more or less than 45degrees. It is appreciated that rather than the cutting element beingrun parallel to the longitudinal axis of the implant, the cuttingelement could be run at some other angle. By way of example only and notlimitation, this angle could be at 45 degrees to the longitudinal axisof the implant and to the projections. Each surface projection couldthen be formed by a cutter crossing in two passes to form two grooves ata 90 degree angle to each other.

The surface configuration of the implant of the present invention may beincorporated into various types of orthopedic implants. Such orthopedicimplants may be for securing a prosthetic device implanted into bone,may be for the purpose of healing bone portions or for achieving fusionof bones, or for stabilizing a device to space apart and allow motionbetween the adjacent bones or bone portions. Such orthopedic implantsmay comprise any artificial or naturally occurring material appropriatefor the intended purpose. Such materials would include, but are notlimited to, implant quality metals, including, but not limited to,titanium and its alloys, surgical grade plastics and plastic compositeswhich may or may not be bioresorbable, ceramics, and cortical bone. Someexamples of interbody orthopedic implants that may benefit from thepresent teaching, include but are not limited to any artificial jointcomponent having an intramedullary stem, such as but not limited to, hipreplacements, shoulder replacements, knee replacements, and fingerjoints; and medical prosthetic implants for replacing a lost portion ofa long bone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an orthopedic implant having a surfaceconfiguration in accordance with the present invention.

FIG. 2 is a side elevation view of the orthopedic implant of FIG. 1.

FIG. 3 is a side elevation view of the interbody orthopedic implant ofFIG. 1 installed in an implantation site formed in bone shown in partialcross-section.

FIG. 4 is an enlarged fragmentary top plan view of an implant surface ofone embodiment of the present invention from a view taken along area 4of FIG. 1.

FIG. 5 is a fragmentary side elevation view of the implant surface ofFIG. 4 from a view taken along area 5 of FIG. 2.

FIG. 6 is a fragmentary end elevation view of FIG. 4.

FIG. 7 is a fragmentary perspective view of the implant surface of FIG.4.

FIG. 8 is an enlarged fragmentary top plan view of a second embodimentof the implant surface of the present invention from a view taken alongarea 8 of FIG. 1.

FIG. 9 is a fragmentary side elevation view of the implant surface ofFIG. 8 from a view taken along area 9 of FIG. 2.

FIG. 10 is a fragmentary end view of the implant surface of FIG. 8.

FIG. 11 is a fragmentary perspective view of the implant surface of FIG.8.

FIG. 12 is an enlarged fragmentary top plan view of a third embodimentof the implant surface of the present invention from a view taken alongarea 12 of FIG. 1.

FIG. 13 is a fragmentary side elevation view of the implant surface ofFIG. 12 from a view taken along area 13 of FIG. 2.

FIG. 14 is a fragmentary end view of FIG. 12.

FIG. 15 is a fragmentary perspective view of the implant surface of FIG.12.

FIG. 16 is an enlarged fragmentary top plan view of a fourth embodimentof the implant surface of the present invention from a view taken alongarea 16 of FIG. 1.

FIG. 17 is a fragmentary side elevation view of the implant surface ofFIG. 16 from a view taken along area 17 of FIG. 2.

FIG. 18 is a fragmentary end view of FIG. 16.

FIG. 19A is an enlarged fragmentary perspective view of the implantsurface of FIG. 16.

FIG. 19B is an enlarged fragmentary perspective view of a variation onthe second and third surface projections of the fourth embodiment of theimplant surface of the present invention with a cleave therethrough.

FIG. 20 is an enlarged fragmentary top plan view of a fifth embodimentof the implant surface of the present invention from a view taken alongarea 20 of FIG. 1.

FIG. 21 is a fragmentary side elevation view of the implant surface ofFIG. 20 from a view taken along line 21 of FIG. 2.

FIG. 22 is a fragmentary end view of FIG. 20.

FIG. 23 is an enlarged fragmentary perspective view of the implantsurface of FIG. 20.

FIGS. 24A and 24B are perspective and side elevation views,respectively, of a prior art implant surface having forward facingratchetings.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in FIGS. 1-7, an orthopedic implant 100, in the form of a hipprosthesis in this example, has a leading end 102, a trailing end 104,and an exterior surface 106. Implant 100 may converge from trailing end104 to leading end 102 along a longitudinal axis L of implant 100 asshown, or may diverge, be parallel, or any combination thereof. Exteriorsurface 106 is configured to be placed against and in contact orengagement with the bone B, including adjacent bones or bone portions,of a human skeleton. It is appreciated that the surface configuration ofthe present invention is not limited to a hip prosthesis and may beincorporated in other types of orthopedic implants including suchimplants placed between adjacent bones or adjacent bone portions of thehuman skeleton. Exterior surface 106 may include large and/or smallopenings 114,116 to permit bone growth into and through implant 100.Exterior surface 106 of implant 100 can be generally planar, or can bearcuate as shown in the Figures, or any other configuration suitable forthe desired use.

As shown in detail in FIGS. 4-7, at least a portion of exterior surface106 of implant 100 has a surface configuration generally referred to bythe numeral 120. In accordance with a first embodiment of the presentinvention, surface configuration 120 includes surface projections 122configured to facilitate insertion of implant 100 into an implantationsite while resisting expulsion of implant 100 in a direction opposite tothe direction of insertion. Each of surface projections 122 has anangled forward facet 124 directed at least in part toward leading end102 of implant 100 and a rearward facet 126 directed at least in parttoward trailing end 104 of implant 100. Forward facet 124 has a lengthgreater than the length of rearward facet 126. Rearward facet 126 has aslope that is steeper than the slope of forward facet 124. In thisembodiment, the base of rearward facet 126 forms an angle ofapproximately 90 degrees with respect to exterior surface 106 of implant100. It is appreciated that the angle of the base of rearward facet 126with respect to exterior surface 106 of implant 100 may be perpendicularto, greater than perpendicular to, or less than perpendicular to thebase of the surface where the facet arises. Forward facet 124 forms anangle in the range of approximately 10 to 60 degrees, with 25-45 degreesbeing preferred, with respect to exterior surface 106. Each one ofsurface projections 122 also has a left side facet 132 and a right sidefacet 134 directed toward the sides of implant 100.

In this embodiment of surface configuration 120, a plurality of surfaceprojections 122 are spaced apart laterally (side to side) bylongitudinal grooves 130 formed along the longitudinal axis L of implant100. In one embodiment, longitudinal grooves 130 have a V-shapedhorizontal cross-section. The lower most portions of left and right sidefacets 132, 134 of consecutive side-by-side projections 122 can becoincident with each other or may be spaced apart, any spacetherebetween can be at least in part flat, curved, sloped or otherwiseconfigured. Each surface projection 122 has left and right side facets132, 134 that converge to form a high point or peak 136 at the top ofeach surface projection 122. Each peak 136 can be aligned along linesthat are perpendicular, parallel, and/or diagonally oriented tolongitudinal axis L of implant 100. The left and right side facets 132,134 resist side-to-side motion of implant 100 after it is inserted intothe implantation space. Peaks 136 engage the bone B adjacent to implant100 in the implantation site. It is appreciated that in a variation ofthe present invention, the peaks may be modified such as to be truncatedor cut off to have a broader rather than shaper upper most surface.Moreover, the peaks can be cleaved in one or more directions so as toincrease the surface area useful for engaging bone. The relieved areasof the cleaved projections are useful for containing and carrying fusionpromoting substances other than bone such as bone morphogenetic proteinsand genetic materials coding for the production of bone, or bone itselfwhich could by way of example be in the form of a paste. It is furtherappreciated that for all the various embodiments of the surfaceconfiguration of the present invention, longitudinal grooves 130 canhave horizontal cross-sections in a variety of configurations such as,without limitation, square-shaped or U-shaped configurations.

Sequential projections can be positioned on an implant wherein eachsurface projection has forward facing facets facing the same directionsuch that consecutive projections are oriented forward facing facet torearward facing facet. The lower most portion of the slope of theforward facing facet of a first surface projection in a sequence can becoincident with the rearward facet of the next surface projection in thesequence. Alternatively, the forward facet of a first surface projectionand the rearward facet of the next surface projection in a sequence canbe spaced apart and the space can be at least in part flat, curved, orany other surface configuration suitable for the intended use. Thesurface projections can be oriented relative to one another to form anarray and are preferably geometrically disposed relative to one anotherin a pattern wherein at least a portion of the projection is alignedalong a longitudinal, horizontal, diagonal, or curved line. Further, itis appreciated that the surface of the present invention can be usefulwith orthopedic implants of various configurations, includingconfigurations wherein at least one of leading end, trailing end, andsides of the orthopedic implant is curved. By way of example and notlimitation, the leading end, trailing end, and sides of the orthopedicimplant can form an oval, an oblong, a circle, or other geometric shape.

As shown in FIGS. 8-11, a second embodiment of the surface configurationof the present invention is generally referred to by the numeral 220.Surface configuration 220 includes surface projections 222 to facilitateinsertion of implant 100 into an implantation site while resistingexpulsion of implant 100 in a direction opposite to the direction ofinsertion. Each of surface projections 222 has an angled forward facet224 directed at least in part toward leading end 202 of implant 100 anda rearward facet 226 directed at least in part toward trailing end 204of implant 100. Forward facet 224 has a length greater than the lengthof rearward facet 226. Rearward facet 226 has a slope that is steeperthan the slope of forward facet 224. In this embodiment, the base ofrearward facet 226 forms an angle of approximately 45 degrees withrespect to exterior surface 206 of implant 100. Each one of surfaceprojections 222 has a left side facet 232 and a right side facet 234directed toward the sides of implant 100, and forward facet 224 andrearward facet 226.

In this embodiment of surface configuration 220, longitudinal grooves230 have a V-shaped horizontal cross-section. The lower most portions ofleft and right side facets 232, 234 of consecutive side-by-sideprojections 222 can be coincident with each other or may be spacedapart, any space therebetween can be at least in part flat, curved,sloped or otherwise configured. Each surface projection has left andright side facets 232, 234 that converge to form a high point or peak236 at the top of each surface projections 222. Each peak 236 can bealigned along lines that are perpendicular, parallel, and/or diagonallyoriented to the longitudinal axis L of implant 100. The left and rightside facets 232, 234 resist side-to-side motion of implant 100 after itis inserted into the implantation space. Peaks 236 engage bone Badjacent to implant 100 in the implantation site.

As shown in FIGS. 12-15, a third embodiment of the surface configurationof the present invention is generally referred to by the numeral 320 isshown. Surface configuration 320 includes surface projections 322 tofacilitate insertion of implant 100 into an implantation site whileresisting expulsion of implant 100 in a direction opposite to thedirection of insertion. Each of surface projections 322 has an angledforward facet 324 directed at least in part toward leading end 302 ofimplant 100 and a rearward facet 326 directed at least in part towardtrailing end 304 of implant 100. Forward facet 324 has a length greaterthan the length of rearward facet 326. Rearward facet 326 has a slopethat is steeper than the slope of forward facet 324. In this embodiment,the base of rearward facet 326 is “back cut” to form an angle greaterthan 90 degrees with respect to exterior surface 306 of implant 100. Theconfiguration of rearward facet 326 further enhances resistance ofmotion of the implant in a direction opposite to the direction ofinsertion. It is appreciated that the angle of the base of rearwardfacet 326 with respect to exterior surface 306 of implant 100 can be anyother angle suitable for the intended purpose of the present invention.Each one of surface projections 322 has a left side facet 332 and aright side facet 334 directed toward the sides of implant 100, and aforward facet 324 and a rearward facet 326.

In this embodiment of surface configuration 320, longitudinal grooves330 have a V-shaped horizontal cross section. The lower most portions ofleft and right side facets 332, 334 of consecutive side-by-sideprojections 322 can be coincident with each other or may be spacedapart, and any space therebetween can be at least in part flat, curved,sloped or otherwise configured. Each surface projection 322 has left andright side facets 332, 334 that converge to form a high point or peak336 at the top of each surface projection 322. Each peak 336 can bealigned along lines that are perpendicular, parallel, and/or diagonallyoriented to the longitudinal axis L of implant 100. The left and rightside facets 332, 334 resist side-to-side motion of implant 100 after itis inserted into the implantation space. Peaks 336 engage bone Badjacent to implant 100 in the implantation site.

As shown in FIGS. 16-19B, a fourth embodiment of the surfaceconfiguration of the present invention is generally referred to by thenumeral 420. Surface configuration 420 includes surface projections 422configured to facilitate insertion of implant 100 in the direction ofinsertion into an implantation site while resisting expulsion of implant100 in a direction opposite to the direction of insertion. Each ofsurface projections 422 has an angled forward facet 424 directed towardleading end 402 of implant 100 and a rearward portion 426 directedtoward trailing end 404 of implant 100. Forward facet 424 has a lengthgreater than the length of rearward portion 426. Rearward portion 426has a slope that is steeper than the slope of forward facet 424. In thisembodiment, the base of rearward portion 426 forms an angle ofapproximately 90 degrees with respect to exterior surface 406 of implant100. Rearward portion 426 can be a portion of surface projection 422,such as a facet, an edge, or a line for example. Each one of surfaceprojections 422 has a left side forward facet 450, a right side forwardfacet 452, a left side rearward facet 454, and a right side rearwardfacet 456 directed toward the front and sides, and directed toward therear and sides of implant 100, respectively, and forward facet 424 andrearward portion 426.

Surface configuration 420 can further include a second plurality ofsurface projections 460 having at least a left forward side facet 462and a right forward side facet 464 directed at least in part towardleading end 402 and sides of implant 100, respectively, and at least onerearward facet 466 directed at least in part toward trailing end 400.Left and right forward side facets 462, 464 have at least a firstportion in a plane at an angle to the longitudinal axis of implant 100.Second surface projections 460 can be interspersed with surfaceprojections 422.

Surface configuration 420 can further comprise a third plurality ofsurface projections 470 having at least a left rearward side facet 472and a right rearward side facet 474 directed at least in part towardtrailing end 404 and sides of implant 100, respectively, and at leastone forward facet 476 directed at least in part toward leading end 402.Left and right rearward side facets 472, 474 have at least a firstportion in a plane at an angle to the longitudinal axis of implant 100.Third surface projections 470 can be interspersed with surfaceprojections 422 and/or second surface projections 460. Surfaceprojections 422 may have a length approximating the combined length ofsecond surface projections 460 and third surface projections 470.

In this embodiment, surface configuration 420 has angled grooves 440 a-kthat form a plurality of surface projections 422. In this example,angled grooves 440 a-k are formed at an angle that is approximately 45degrees to longitudinal axis L of orthopedic implant 100 and in thisexample, angled grooves 440 a-k are approximately 90 degrees to oneanother. The angled grooves 440 a-k can be formed, if machined, by firstpassing a cutting element at a 45 degree angle to the longitudinal axisL of implant 100 and then passing the cutting element at a 90 degreeangle to the path of the first pass of the cutting element, or otherwiseformed by casting, molding, and other methods for forming a surfaceconfiguration. It is appreciated that angled grooves 400 a-k can beformed at various angles to the longitudinal axis L of implant 100 andto each other. For example, such angles can be less than 180 degrees.

In this embodiment of surface configuration 420, angled grooves 440 a-khave a V-shaped horizontal cross-section. Each surface projection 422has left and right side facets 432 and 434 that are convergent and forma high point or peak 436 at the top of each surface projections 422.Each peak 436 can be aligned along lines that are horizontally,longitudinally, and/or diagonally oriented along implant 100. The leftand right side forward and rearward facets 450, 452, 454, 456 functionto prevent side-to-side motion of implant 100 after it is inserted intothe implantation space. Peaks 436 may also function like teeth to engagebone B adjacent to the implant in the implantation site.

FIG. 19B shows a variation of second and third surface projections 460′,470′ that can be cleaved in one or more directions to increase thenumber of exposed sides of each projection and thus increase the surfacearea of the implant bone engaging surface available to contact bone B. Apreferred embodiment of this variation of the second and third surfaceprojections 460′, 470′ are cleaved by a longitudinal groove.

As shown in FIGS. 20-23, a fifth embodiment of the surface configurationof the present invention is generally referred to by the numeral 520.Surface configuration 520 includes surface projections 522 to facilitateinsertion of implant 100 into an implantation site while resistingexpulsion of implant 100 in a direction opposite to the direction ofinsertion. Surface projections 522 can be cleaved in one or moredirections to increase the number of exposed sides of each projectionand thus increase the surface area of the implant bone engaging surfaceavailable to contact bone B. For example, the surface projections can becleaved by a longitudinal cut 540 generally parallel to the longitudinalaxis L of implant 100 to form a surface projection having nine exposedsides. The surface projections may further be cleaved by a horizontalcut 542 generally perpendicular to the longitudinal axis L of implant100 to form a surface projection having eighteen exposed sides. The cutscan penetrate the surface projection at a depth substantially equal tothat of the height of the surface projections as measured from the upperor lower surfaces of the implant. The cuts can be oriented along atleast one of the longitudinal axis of the implant, an axis perpendicularto the longitudinal axis of said implant, and an axis at an anglebetween the longitudinal axis and the axis perpendicular to thelongitudinal axis of the implant. It is appreciated that cuts 540 and542 may be formed as part of the molding process for forming the surfaceprojections.

When cleaved by longitudinal cut 540 and horizontal cut 542, each ofsurface projections 522 has angled forward facet 524 a, 524 b directedat least in part toward leading end 502 of implant 100 and rearwardfacets 526 a, 526 b directed at least in part toward trailing end 504 ofimplant 100. Forward facet 524 has a length greater than the length ofrearward facet 526. Rearward facets 526 a, 526 b have a slope that issteeper than the slope of forward facets 524 a, 524 b. The cleavedportion of surface projection 522 can be spaced apart by a predetermineddistance and the space can be at least in part flat, curved, or anyother surface configuration suitable for the intended use. In thisembodiment, the base of rearward facets 526 a, 526 b forms an angle ofapproximately 45 degrees with respect to exterior surface 506 of implant100. Each one of surface projections 522 has left side facets 532 a, 532b and right side facets 534 a, 534 b directed toward the sides ofimplant 100, and forward facets 524 a, 524 b and rearward facet 526 a,526 b. In this embodiment of surface configuration 520, longitudinalgrooves 530 have a V-shaped horizontal cross-section and each surfaceprojection 522 has left and right side facets 532 a, 532 b, 534 a, 534 bthat converge toward one another. The left and right side facets 532 a,532 b, 534 a, 534 b resist side-to-side motion of implant 100 after itis inserted into the implantation space.

The surface configuration of the present invention can be formed bymolding, machining or otherwise. A preferred surface configuration ofthe present invention may readily be machined by milling from side toside, across the bone engaging surfaces, surface projections. A millingmachine with a cutting tool having an angled cutting face such as aV-shaped profile can then be run through the plurality of surfaceprojections parallel to the longitudinal axis of the implant to form theabove-described surface. In a preferred embodiment, the V-shaped cuttingtool of the milling machine has faces with an angle of approximately 90degrees, which faces are at a 45-degree angle to the plane of thesurfaces being so machined. Without departing from the presentinvention, the angle of the cutting faces can be more or less than 90degrees, the angle of the cutting face to the surface to be cut can bemore or less than 45 degrees, and rather than running the cutter elementparallel to the longitudinal axis of the implant, the cutting elementmay be run at an angle. By way of example only and not limitation, thisangle may be at 45 degrees to the longitudinal axis of the implant andeach surface projection can be formed by two grooves crossing theprojections at a 90 degree angle to each other.

The orthopedic implants of the present invention are made of artificialor naturally occurring materials suitable for implantation in the humanbody. The implants can comprise bone including, but not limited to,cortical bone, materials other than bone, such as metals including, butnot limited to, titanium and its alloys or ASTM material, surgical gradeplastics, plastic composites, ceramics, or other materials suitable foruse as an orthopedic implant. The implants of the present invention canfurther comprise or be combined with bone growth promoting materials,including but not limited to, bone, bone morphogenetic proteins,hydroxyapatite, and genes coding for the production of bone. Theimplants can be treated with a bone growth promoting substance, can be asource of osteogenesis, or can be bioabsorbable at least in part. Theimplants of the present invention can be formed of a porous material.

The orthopedic implants of the present invention can be for the purposeof achieving fusion. The exterior surface of the fusion implants caninclude at least one opening to permit for the growth of bone from boneor bone portion to adjacent bone or bone portion through the implant.The implant can have an internal chamber and may also have an accessopening for accessing the internal chamber, in which case the implantcan further have a cover such as a cap to close the access opening atleast in part. Openings in the exterior surface of the implant cancommunicate with the internal chamber to permit further growth of bonethrough the implant. The internal chamber can contain bone growthpromoting materials, including but not limited to, bone, bonemorphogenetic proteins, hydroxyapatite, and genes coding for theproduction of bone. The implants of the present invention can be formedof a material that intrinsically participates in the growth of bone fromone of the adjacent bones or bone portions to the other of the adjacentbones or bone portions.

While various embodiments of the present invention are presented by wayof example only and not limitation, common to each of them, is that theconfiguration of the surface is based on a plurality of surfaceprojections disposed in arrays, each surface projection comprising atleast one leading facet and at least one opposing trailing facet, inwhich the leading facet has a length greater than the trailing facet andthe trailing facet has a steeper slope than the slope of the leadingfacet. The surface configuration is located on at least a portion ofexterior bone engaging surface of the orthopedic implant.

While the implant shown in FIGS. 1, 2, and 3 is a hip prosthesis, it isappreciated that the surface configuration of the present invention isapplicable to any orthopedic implants having an exterior surfaceincorporating the present inventive teachings for engaging boneincluding but not limited to, any artificial joint component having anintramedullary stem, such as but not limited to, hip replacements,shoulder replacements, knee replacements, and finger joints; and medicalprosthetic implants for replacing a lost portion of a long bone.

It is believed that the operation and construction of the presentinvention will be apparent from the foregoing description and, while theinvention shown and described herein has been characterized asparticular embodiments, changes and modifications may be made thereinwithout departing from the spirit and scope of the invention as definedin the following claims.

1. An orthopedic implant for contact with bone, including adjacent bonesand adjacent bone portions, of a human skeleton, said implantcomprising: a leading end for introduction of said orthopedic implantinto the bone, an opposite trailing end, spaced apart sidestherebetween, and a mid-longitudinal axis passing through said leadingand trailing ends; an exterior surface between said leading and trailingends and said spaced apart sides, said exterior surface adapted forplacement in engagement with the bone; and a plurality of surfaceprojections formed on said exterior surface of said implant, at least afirst and a second of said surface projections each having at least oneforward facing facet directed at least in part toward said leading endand at least one rearward facet directed at least in part toward saidtrailing end, each of said forward facet and rearward facet having alength and a slope, the length of said forward facet being longer thanthe length of said rearward facet, the slope of said rearward facetbeing steeper than the slope of said forward facet, the slope of saidforward facets of said at least said first and said second of saidsurface projections being the same, at least a portion of said rearwardfacet of said first surface projection overlying a portion of saidforward facet of said second surface projection, said first and secondsurface projections each having opposed side facets directed generallytoward said spaced apart sides of said implant, respectively, said sidefacets being located between said forward facet and said rearward facetof each of said first and second surface projections.
 2. The orthopedicimplant of claim 1, wherein said rearward facet is at an angle to saidexterior surface of said implant.
 3. The orthopedic implant of claim 2,wherein the angle is greater than 90 degrees.
 4. The orthopedic implantof claim 1, wherein said surface projections are oriented relative toone another to form an array.
 5. The orthopedic implant of claim 1,wherein said surface projections are geometrically disposed relative toone another.
 6. The orthopedic implant of claim 1, wherein said exteriorsurface of said implant is at least in part arcuate.
 7. The orthopedicimplant of claim 1, wherein at least one of said leading end, trailingend, and sides are curved.
 8. The orthopedic implant of claim 1, whereinsaid sides are curved.
 9. The orthopedic implant of claim 1, whereineach of said leading end, trailing end, and sides are curved.
 10. Theorthopedic implant of claim 9, wherein said leading end, trailing end,and sides form a circle.
 11. The orthopedic implant of claim 1, whereinsaid exterior surface of said implant is at least in part planar. 12.The orthopedic implant of claim 1, wherein said implant is tapered alongat least a portion of the length of said implant.
 13. The orthopedicimplant of claim 1, wherein said implant comprises a material other thanbone.
 14. The orthopedic implant of claim 1, wherein said implantcomprises bone.
 15. The orthopedic implant of claim 14, wherein saidbone includes cortical bone.
 16. The orthopedic implant of claim 1,wherein said implant comprises bone growth promoting material.
 17. Theorthopedic implant of claim 16, wherein said bone growth promotingmaterial is one of bone morphogenetic protein, hydroxyapatite, and genescoding for the production of bone.
 18. The orthopedic implant of claim1, wherein said implant is treated with a bone growth promotingsubstance.
 19. The orthopedic implant of claim 1, wherein said implantis a source of osteogenesis.
 20. The orthopedic implant of claim 1,wherein said implant is at least in part bioabsorbable.
 21. Theorthopedic implant of claim 1, wherein said implant comprises metal. 22.The orthopedic implant of claim 21, wherein said metal is ASTM materialsuitable for use as an orthopedic implant.
 23. The orthopedic implant ofclaim 21, wherein said metal includes titanium.
 24. The orthopedicimplant of claim 1, wherein said implant comprises a plastic material.25. The orthopedic implant of claim 1, wherein said implant comprises aceramic material.
 26. The orthopedic implant of claim 1, wherein saidimplant is formed of a porous material.
 27. The orthopedic implant ofclaim 1, wherein said implant is formed of a material that intrinsicallyparticipates in the growth of bone from adjacent bone to adjacent bonethrough said implant.
 28. The orthopedic implant of claim 1, whereinsaid implant is a motion preserving device adapted to space apart andallow motion between the adjacent bone or bone portions.
 29. Theorthopedic implant of claim 1, wherein said orthopedic implant is afusion implant.
 30. The orthopedic implant of claim 29, wherein saidexterior surface includes at least one opening to permit bone growthfrom adjacent bone to adjacent bone through said implant.
 31. Theorthopedic implant of claim 29, wherein said implant has an internalchamber and an access opening for accessing said internal chamber. 32.The orthopedic implant of claim 31, wherein said implant has a cap forclosing said access opening.
 33. The orthopedic implant of claim 31,wherein said exterior surface includes at least one opening incommunication with said internal chamber to permit bone growth fromadjacent bone to adjacent bone through said implant.
 34. The orthopedicimplant of claim 31, wherein said internal chamber is capable ofcontaining bone growth promoting material.
 35. The orthopedic implant ofclaim 34, wherein said bone growth promoting material is one of bonemorphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 36. The orthopedic implant of claim 1 furthercomprising at least one opening capable of retaining fusion promotingmaterials.
 37. The orthopedic implant of claim 1, further comprising atleast one cut cleaving said surface projection into at least twoportions.
 38. The orthopedic implant of claim 37, further comprising atleast a second cut cleaving said surface projection into at least fourportions.
 39. The orthopedic implant of claim 37, where said cutpenetrates said surface projection at a depth substantially equal tothat of the height of said surface projection.
 40. The orthopedicimplant of claim 38, where said second cut penetrates said surfaceprojection at a depth substantially equal to that of the height of saidsurface projection.
 41. The orthopedic implant of claim 37, wherein saidcut is oriented along one of the mid-longitudinal axis of said implant,an axis perpendicular to the mid-longitudinal axis of said implant, andan axis at an angle between the mid-longitudinal axis and the axisperpendicular to the mid-longitudinal axis of said implant.
 42. Theorthopedic implant of claim 1, in combination with a fusion promotingsubstance.
 43. The orthopedic implant of claim 42, wherein said fusionpromoting substance includes at least one of bone, bone morphogeneticprotein, hydroxyapatite, and genes coding for the production of bone.44. The orthopedic implant of claim 1, wherein each of said first andsecond surface projections have a base that is adjacent to one another.45. The orthopedic implant of claim 1, wherein each of said first andsecond surface projections have a base, the bases being spaced apartfrom one another along a direction generally parallel to themid-longitudinal axis of said implant.
 46. The orthopedic implant ofclaim 1, wherein each of said first and second surface projections havea base, the bases being spaced apart from one another along a directiongenerally transverse to the mid-longitudinal axis of said implant. 47.The orthopedic implant of claim 1, wherein said side facets convergetoward each other in a direction away from said exterior surface of saidimplant.
 48. The orthopedic implant of claim 47, wherein said opposedside facets intersect each other.
 49. The orthopedic implant of claim48, wherein said opposed side facets converge to form a peak at the topof said surface projection.
 50. The orthopedic implant of claim 49,wherein said peaks of at least two of said surface projections arealigned along lines that are at least one of perpendicular, parallel,and diagonal to the mid-longitudinal axis of said implant.
 51. Theorthopedic implant of claim 49, wherein said peak of said first surfaceprojection overlies at least a portion of said second surfaceprojection.
 52. The orthopedic implant of claim 49, wherein said peaksof said first and second surface projections are at the same heightabove said exterior surface of said implant.
 53. The orthopedic implantof claim 1, wherein adjacent side facets of adjacent surface projectionsare spaced apart to define a groove therebetween.
 54. The orthopedicimplant of claim 1, wherein a plurality of adjacent surface projectionsare spaced apart to form a plurality of grooves therebetween.
 55. Theorthopedic implant of claim 54, wherein at least one of said grooves isparallel to the mid-longitudinal axis of said implant.
 56. Theorthopedic implant of claim 54, wherein at least two of said groovescross each other.
 57. The orthopedic implant of claim 54, wherein atleast one of said grooves has a horizontal cross-sectional shape that isone of a v-shape, u-shape, and a box-like shape.
 58. The orthopedicimplant of claim 1, wherein each of said first and second surfaceprojections have a base and said side facets have a maximum widththerebetween at the base, the base being spaced apart from a base ofanother of said surface projections by a distance no greater thanone-half the maximum width of one of said first and second surfaceprojections.
 59. The orthopedic implant of claim 1, wherein said forwardfacets of each of said first and second surface projections face thesame direction.
 60. An orthopedic implant for contact with bone,including adjacent bones and bone portions, of a human skeleton, saidimplant comprising: a leading end, an opposite trailing end, amid-longitudinal axis passing through said leading and trailing ends,and right and left sides between said leading and trailing ends, saidright and left sides being spaced apart on opposite sides of themid-longitudinal axis and; an exterior surface between said leading andtrailing ends and said right and left sides, said exterior surfaceadapted for placement in engagement with the bone; and a plurality ofsurface projections formed on said exterior surface of said implant,each of said surface projections having a plurality of facets, each ofsaid facets having a perimeter defining each facet, at least a first anda second of said surface projections each having at least a first facetand at least a second facet opposite said first facet, each of saidfirst and second facets having a length and a slope, the length of saidfirst facet being longer than the length of said second facet, the slopeof said second facet being steeper than the slope of said first facet,said second facet including a perimeter having at least a first and asecond portion arranged to form an apex having an included angle greaterthan 90 degrees between said first and second portions of the perimeter.61. The orthopedic implant of claim 60, wherein said second facet is atan angle to said exterior surface of said implant.
 62. The orthopedicimplant of claim 61, wherein the angle is greater than 90 degrees. 63.The orthopedic implant of claim 60, wherein said projections areoriented relative to one another to form an array.
 64. The orthopedicimplant of claim 60, wherein said projections are geometrically disposedrelative to one another.
 65. The orthopedic implant of claim 60, whereinsaid exterior surface of said implant is at least in part arcuate. 66.The orthopedic implant of claim 60, wherein said exterior surface ofsaid implant is at least in part planar.
 67. The orthopedic implant ofclaim 60, wherein said implant is tapered along at least a portion ofthe length of said implant.
 68. The orthopedic implant of claim 60,wherein said implant comprises bone growth promoting material.
 69. Theorthopedic implant of claim 68, wherein said bone growth promotingmaterial is one of bone morphogenetic protein, hydroxyapatite, and genescoding for the production of bone.
 70. The orthopedic implant of claim60, wherein said implant is a motion preserving device adapted to spaceapart and allow motion between the adjacent bone or bone portions. 71.The orthopedic implant of claim 60, wherein said orthopedic implant is afusion implant.
 72. The orthopedic implant of claim 60, in combinationwith a fusion promoting substance.
 73. The orthopedic implant of claim72, wherein said fusion promoting substance includes at least one ofbone, bone morphogenetic protein, hydroxyapatite, and genes coding forthe production of bone.
 74. The orthopedic implant of claim 60, whereineach of said first and second surface projections have a base, the basesbeing adjacent to one another.
 75. The orthopedic implant of claim 60,wherein each of said first and second surface projections have a base,the bases being spaced apart from one another along a directiongenerally parallel to the mid-longitudinal axis of said implant.
 76. Theorthopedic implant of claim 60, wherein each of said first and secondsurface projections have a base, the bases being spaced apart from oneanother along a direction generally transverse to the mid-longitudinalaxis of said implant.
 77. The orthopedic implant of claim 60, whereinsaid first and second surface projections each have a base and opposedside facets directed generally toward said leading and trailing ends,respectively, said side facets being located between said first facetand said second facet of each of said first and second surfaceprojections, said side facets converging toward each other in adirection away from the base of each of said first and second surfaceprojections.
 78. The orthopedic implant of claim 77, wherein adjacentside facets of adjacent surface projections are spaced apart to define agroove therebetween.
 79. The orthopedic implant of claim 77, whereinsaid side facets have a maximum width therebetween at the base of saidfirst and second surface projections, the base being spaced apart from abase of another of said surface projections by a distance no greaterthan one-half the maximum width of one of said first and second surfaceprojections.
 80. The orthopedic implant of claim 77, wherein saidopposed side facets converge to form a peak, said peaks of said firstand second surface projections being at the same height above saidexterior surface of said implant.
 81. The orthopedic implant of claim60, wherein said at least one first facet of each of said first andsecond surface projections face the same direction.
 82. An orthopedicimplant for contact with bone, including adjacent bones and boneportions, of a human skeleton, said implant comprising: a leading endfor introduction of said orthopedic implant into the bone, an oppositetrailing end, spaced apart sides therebetween, and a mid-longitudinalaxis passing through said leading and trailing ends; an exterior surfacebetween said leading and trailing ends and said spaced apart sides, saidexterior surface adapted for placement in engagement with the bone; anda plurality of surface projections formed on said exterior surface ofsaid implant, at least a first and a second of said surface projectionseach having at least one forward facing facet directed at least in parttoward said leading end and at least one rearward facet directed atleast in part toward said trailing end, each of said forward facet andrearward facet having a length and a slope, the length of said forwardfacet being longer than the length of said rearward facet, the slope ofsaid rearward facet being steeper than the slope of said forward facet,said first and second surface projections each having a base and anincluded angle between said rearward facet and the base greater than 90degrees relative to said exterior surface of said implant, said surfaceprojections having opposed side facets directed generally toward saidsides of said implant, said side facets being located between saidforward facet and said rearward facet of said surface projections, saidside facets converging toward each other in a direction away from thebase of said first and second projections.
 83. The orthopedic implant ofclaim 82, wherein said exterior surface of said implant is at least inpart arcuate.
 84. The orthopedic implant of claim 82, wherein at leastone of said leading end, trailing end, and sides are curved.
 85. Theorthopedic implant of claim 82, wherein said sides are curved.
 86. Theorthopedic implant of claim 82, wherein each of said leading end,trailing end, and sides are curved.
 87. The orthopedic implant of claim86, wherein said leading end, trailing end, and sides form a circle. 88.The orthopedic implant of claim 82, wherein said exterior surface ofsaid implant is at least in part planar.
 89. The orthopedic implant ofclaim 82, wherein said implant is tapered along at least a portion ofthe length of said implant.
 90. The orthopedic implant of claim 82,wherein said implant comprises a material other than bone.
 91. Theorthopedic implant of claim 82, wherein said implant comprises bone. 92.The orthopedic implant of claim 91, wherein said bone includes corticalbone.
 93. The orthopedic implant of claim 82, wherein said implantcomprises bone growth promoting material.
 94. The orthopedic implant ofclaim 93, wherein said bone growth promoting material is one of bonemorphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 95. The orthopedic implant of claim 82, wherein saidimplant is treated with a bone growth promoting substance.
 96. Theorthopedic implant of claim 82, wherein said implant is a source ofosteogenesis.
 97. The orthopedic implant of claim 82, wherein saidimplant is at least in part bioabsorbable.
 98. The orthopedic implant ofclaim 82, wherein said implant comprises metal.
 99. The orthopedicimplant of claim 98, wherein said metal includes titanium.
 100. Theorthopedic implant of claim 82, wherein said implant comprises at leastone of a plastic material and a ceramic material.
 101. The orthopedicimplant of claim 82, wherein said implant is formed of a porous materialand a material that intrinsically participates in the growth of bonefrom adjacent bone to adjacent bone through said implant.
 102. Theorthopedic implant of claim 82, wherein said implant is a motionpreserving device adapted to space apart and allow motion between theadjacent bones and bone portions.
 103. The orthopedic implant of claim82, wherein said orthopedic implant is a fusion implant.
 104. Theorthopedic implant of claim 103, wherein said exterior surface includesat least one opening to permit bone growth from adjacent bone toadjacent bone through said implant.
 105. The orthopedic implant of claim103, wherein said implant has an internal chamber and an access openingfor accessing said internal chamber.
 106. The orthopedic implant ofclaim 105, wherein said exterior surface includes at least one openingin communication with said internal chamber to permit bone growth fromadjacent bone to adjacent bone through said implant.
 107. The orthopedicimplant of claim 105, wherein said internal chamber is capable ofcontaining bone growth promoting material.
 108. The orthopedic implantof claim 107, wherein said bone growth promoting material is one of bonemorphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 109. The orthopedic implant of claim 82, furthercomprising at least one opening capable of retaining fusion promotingmaterials.
 110. The orthopedic implant of claim 82, wherein the bases ofsaid first and second surface projections are adjacent to one another.111. The orthopedic implant of claim 82, wherein said opposed sidefacets converge to form a peak at the top of each of said surfaceprojections.
 112. The orthopedic implant of claim 111, wherein saidpeaks are aligned along lines that are at least one of perpendicular,parallel, and diagonal to the mid-longitudinal axis of said implant.113. The orthopedic implant of claim 82, wherein adjacent side facets ofadjacent surface projections are spaced apart to define a groovetherebetween.
 114. The orthopedic implant of claim 82, wherein aplurality of adjacent surface projections are spaced apart to form aplurality of grooves therebetween.
 115. The orthopedic implant of claim114, wherein at least one of said grooves is parallel to themid-longitudinal axis of said implant.
 116. The orthopedic implant ofclaim 114, wherein at least two of said grooves cross each other. 117.The orthopedic implant of claim 114, wherein at least one of saidgrooves has a horizontal cross-sectional shape that is one of a v-shape,u-shape, and a box-like shape.
 118. An orthopedic implant for contactwith bone, including adjacent bones and bone portions, of a humanskeleton, said implant comprising: a leading end for introduction ofsaid orthopedic implant into the bone, an opposite trailing end, spacedapart sides therebetween, and a mid-longitudinal axis passing throughsaid leading and trailing ends; an exterior surface between said leadingand trailing ends and said spaced apart sides, said exterior surfaceadapted for placement in engagement with the bone; and a plurality ofsurface projections formed on said exterior surface of said implant,each of said surface projections having a forward facet directed atleast in part toward said leading end and a rearward facet directed atleast in part toward said trailing end, said rearward facet including aperimeter having at least a first and a second portion arranged to forman apex having an included angle greater than 90 degrees between saidfirst and second portions.
 119. The orthopedic implant of claim 118,wherein one of said facets is formed in the shape of a triangle having avertex with an included angle greater than 90 degrees.
 120. Theorthopedic implant of claim 118, wherein each of said forward facet andsaid rearward facet of said first and second projections have a lengthand a slope, the length of said forward facet being longer than thelength of said rearward facet, the slope of said rearward facet beingsteeper than the slope of said forward facet.
 121. The orthopedicimplant of claim 118, wherein said rearward facet is at an angle to saidexterior surface of said implant.
 122. The orthopedic implant of claim121, wherein the angle is greater than 90 degrees.
 123. The orthopedicimplant of claim 118, wherein said surface projections are orientedrelative to one another to form an array.
 124. The orthopedic implant ofclaim 118, wherein said surface projections are geometrically disposedrelative to one another.
 125. The orthopedic implant of claim 118,wherein said exterior surface of said implant is at least in partarcuate.
 126. The orthopedic implant of claim 118, wherein at least oneof said leading end, trailing end, and sides are curved.
 127. Theorthopedic implant of claim 118, wherein said sides are curved.
 128. Theorthopedic implant of claim 118, wherein each of said leading end,trailing end, and sides are curved.
 129. The orthopedic implant of claim128, wherein said leading end, trailing end, and sides form a circle.130. The orthopedic implant of claim 118, wherein said exterior surfaceof said implant is at least in part planar.
 131. The orthopedic implantof claim 118, wherein said implant is tapered along at least a portionof the length of said implant.
 132. The orthopedic implant of claim 118,wherein said implant comprises a material other than bone.
 133. Theorthopedic implant of claim 118, wherein said implant comprises bone.134. The orthopedic implant of claim 133, wherein said bone includescortical bone.
 135. The orthopedic implant of claim 118, wherein saidimplant comprises bone growth promoting material.
 136. The orthopedicimplant of claim 135, wherein said bone growth promoting material is oneof bone morphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 137. The orthopedic implant of claim 118, whereinsaid implant is treated with a bone growth promoting substance.
 138. Theorthopedic implant of claim 118, wherein said implant is a source ofosteogenesis.
 139. The orthopedic implant of claim 118, wherein saidimplant is at least in part bioabsorbable.
 140. The orthopedic implantof claim 118, wherein said implant comprises metal.
 141. The orthopedicimplant of claim 140, wherein said metal is ASTM material suitable foruse as an orthopedic fusion implant.
 142. The orthopedic implant ofclaim 140, wherein said metal includes titanium.
 143. The orthopedicimplant of claim 118, wherein said implant comprises a plastic material.144. The orthopedic implant of claim 118, wherein said implant comprisesa ceramic material.
 145. The orthopedic implant of claim 118, whereinsaid implant is formed of a porous material.
 146. The orthopedic implantof claim 118, wherein said implant is formed of a material thatintrinsically participates in the growth of bone from adjacent bone toadjacent bone through said implant.
 147. The orthopedic implant of claim118, wherein said implant is a motion preserving device adapted to spaceapart and allow motion between the adjacent bone and bone portions. 148.The orthopedic implant of claim 118, wherein said orthopedic implant isa fusion implant.
 149. The orthopedic implant of claim 148, wherein saidexterior surface includes at least one opening to permit bone growthfrom adjacent bone to adjacent bone through said implant.
 150. Theorthopedic implant of claim 148, wherein said implant has an internalchamber and an access opening for accessing said internal chamber. 151.The orthopedic implant of claim 150, wherein said implant has a cap forclosing said access opening.
 152. The orthopedic implant of claim 150,wherein said exterior surface includes at least one opening incommunication with said internal chamber to permit bone growth fromadjacent bone to adjacent bone through said implant.
 153. The orthopedicimplant of claim 150, wherein said internal chamber is capable ofcontaining bone growth promoting material.
 154. The orthopedic implantof claim 153, wherein said bone growth promoting material is one of bonemorphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 155. The orthopedic implant of claim 118, furthercomprising at least one opening capable of retaining fusion promotingmaterials.
 156. The orthopedic implant of claim 118, in combination witha fusion promoting substance.
 157. The orthopedic implant of claim 156,wherein said fusion promoting substance includes at least one of bone,bone morphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 158. The orthopedic implant of claim 118, whereineach of said first and second surface projections have a base, the basesbeing adjacent to one another.
 159. The orthopedic implant of claim 118,wherein each of said first and second surface projections have a base,the bases being spaced apart from one another along a directiongenerally parallel to the mid-longitudinal axis of said implant. 160.The orthopedic implant of claim 118, wherein each of said first andsecond surface projections have a base, the bases being spaced apartfrom one another along a direction generally transverse to themid-longitudinal axis of said implant.
 161. The orthopedic implant ofclaim 118, wherein said forward facets of each of said first and secondsurface projections face the same direction.
 162. The orthopedic implantof claim 118, wherein said first and second surface projections eachhave opposed side facets directed generally toward said spaced apartsides of said implant, respectively, said side facets being locatedbetween said forward facet and said rearward facet of each of said firstand second surface projections, said side facets converging toward eachother in a direction away from said exterior surface of said implant.163. The orthopedic implant of claim 162, wherein said opposed sidefacets intersect each other.
 164. The orthopedic implant of claim 163,wherein said opposed side facets converge to form a peak at the top ofsaid surface projection.
 165. The orthopedic implant of claim 164,wherein said peaks of at least two of said surface projections arealigned along lines that are at least one of perpendicular, parallel,and diagonal to the mid-longitudinal axis of said implant.
 166. Theorthopedic implant of claim 164, wherein said peak of said first surfaceprojection overlies at least a portion of said second surfaceprojection.
 167. The orthopedic implant of claim 164, wherein said peaksof said first and second surface projections are at the same heightabove said exterior surface of said implant.
 168. The orthopedic implantof claim 162, wherein adjacent side facets of adjacent surfaceprojections are spaced apart to define a groove therebetween.
 169. Theorthopedic implant of claim 162, wherein a plurality of adjacent surfaceprojections are spaced apart to form a plurality of groovestherebetween.
 170. The orthopedic implant of claim 169, wherein at leastone of said grooves is parallel to the mid-longitudinal axis of saidimplant.
 171. The orthopedic implant of claim 169, wherein at least twoof said grooves cross each other.
 172. The orthopedic implant of claim169, wherein at least one of said grooves has a horizontalcross-sectional shape that is one of a v-shape, u-shape, and a box-likeshape.
 173. The orthopedic implant of claim 162, wherein each of saidfirst and second surface projections have a base and said side facetshave a maximum width therebetween at the base, the base being spacedapart from a base of another of said surface projections by a distanceno greater than one-half the maximum width of one of said first andsecond surface projections.
 174. An interbody orthopedic implant forcontact with bone including adjacent bones and bone portions, of a humanskeleton, said implant comprising: a leading end for introduction ofsaid orthopedic implant into the bone, an opposite trailing end, spacedapart sides therebetween, and a mid-longitudinal axis passing throughsaid leading and trailing ends; an exterior surface between said leadingand trailing ends and said spaced apart sides, said exterior surfaceadapted for placement in engagement with the bone; and a plurality ofsurface projections formed on said exterior surface of said implant, atleast a first and a second of said surface projections each having atleast one forward facing facet directed at least in part toward saidleading end and at least one rearward facet directed at least in parttoward said trailing end, each of said forward facet and rearward facethaving a length and a slope, the length of said forward facet beinglonger than the length of said rearward facet, the slope of saidrearward facet being steeper than the slope of said forward facet, saidfirst and second surface projections each forming a base having aperimeter and a portion above the base, said base having a width and alength greater than width, the length extending along themid-longitudinal axis of said implant, the width being transverse to thelength, said portion above the base of said first and second surfaceprojections extending outside of the perimeter of the base of arespective one of said first and second surface projections, said firstand second surface projections each having opposed side facets directedgenerally toward said spaced apart sides of said implant, respectively,said side facets being located between said forward facet and saidrearward facet of each of said first and second surface projections,said side facets converging toward each other in a direction away fromsaid exterior surface of said implant.
 175. The orthopedic implant ofclaim 174, wherein said rearward facet is at an angle to said exteriorsurface of said implant.
 176. The orthopedic implant of claim 175,wherein the angle is greater than 90 degrees.
 177. The orthopedicimplant of claim 174, wherein said surface projections are orientedrelative to one another to form an array.
 178. The orthopedic implant ofclaim 174, wherein said surface projections are geometrically disposedrelative to one another.
 179. The orthopedic implant of claim 174,wherein said exterior surface of said implant is at least in partarcuate.
 180. The orthopedic implant of claim 174, wherein at least oneof said leading end, trailing end, and sides are curved.
 181. Theorthopedic implant of claim 174, wherein said sides are curved.
 182. Theorthopedic implant of claim 174, wherein each of said leading end,trailing end, and sides are curved.
 183. The orthopedic implant of claim182, wherein said leading end, trailing end, and sides form a circle.184. The orthopedic implant of claim 174, wherein said exterior surfaceof said implant is at least in part planar.
 185. The orthopedic implantof claim 174, wherein said implant is tapered along at least a portionof the length of said implant.
 186. The orthopedic implant of claim 174,wherein said implant comprises a material other than bone.
 187. Theorthopedic implant of claim 174, wherein said implant comprises bone.188. The orthopedic implant of claim 187, wherein said bone includescortical bone.
 189. The orthopedic implant of claim 174, wherein saidimplant comprises bone growth promoting material.
 190. The orthopedicimplant of claim 189, wherein said bone growth promoting material is oneof bone morphogenetic protein, hydroxyapatite, and genes coding for theproduction of bone.
 191. The orthopedic implant of claim 174, whereinsaid implant is treated with a bone growth promoting substance.
 192. Theorthopedic implant of claim 174, wherein said implant is a source ofosteogenesis.
 193. The orthopedic implant of claim 174, wherein saidimplant is at least in part bioabsorbable.
 194. The orthopedic implantof claim 174, wherein said implant comprises metal.
 195. The orthopedicimplant of claim 194, wherein said metal is ASTM material suitable foruse as a fusion implant.
 196. The orthopedic implant of claim 194,wherein said metal includes titanium.
 197. The orthopedic implant ofclaim 174, wherein said implant comprises a plastic material.
 198. Theorthopedic implant of claim 174, wherein said implant comprises aceramic material.
 199. The orthopedic implant of claim 174, wherein saidimplant is formed of a porous material.
 200. The orthopedic implant ofclaim 174, wherein said implant is formed of a material thatintrinsically participates in the growth of bone from adjacent bone toadjacent bone through said implant.
 201. The orthopedic implant of claim174, wherein said implant is a motion preserving device adapted to spaceapart and allow motion between the adjacent bones and bone portions.202. The orthopedic implant of claim 174, wherein said orthopedicimplant is a fusion implant.
 203. The orthopedic implant of claim 202,wherein said exterior surface includes at least one opening to permitbone growth from adjacent bone to adjacent bone through said implant.204. The orthopedic implant of claim 202, wherein said implant has aninternal chamber and an access opening for accessing said internalchamber.
 205. The orthopedic implant of claim 204, wherein said implanthas a cap for closing said access opening.
 206. The orthopedic implantof claim 204, wherein said exterior surface includes at least oneopening in communication with said internal chamber to permit bonegrowth from adjacent bone to adjacent bone through said implant. 207.The orthopedic implant of claim 204, wherein said internal chamber iscapable of containing bone growth promoting material.
 208. Theorthopedic implant of claim 207, wherein said bone growth promotingmaterial is one of bone morphogenetic protein, hydroxyapatite, and genescoding for the production of bone.
 209. The orthopedic implant of claim174, further comprising at least one opening capable of retaining fusionpromoting materials.
 210. The orthopedic implant of claim 174, incombination with a fusion promoting substance.
 211. The orthopedicimplant of claim 210, wherein said fusion promoting substance includesat least one of bone, bone morphogenetic protein, hydroxyapatite, andgenes coding for the production of bone.
 212. The orthopedic implant ofclaim 174, wherein the bases of said first and second surfaceprojections are adjacent to one another.
 213. The orthopedic implant ofclaim 174, wherein the bases of said first and second surfaceprojections are spaced apart from one another along a directiongenerally parallel to the mid-longitudinal axis of said implant. 214.The orthopedic implant of claim 174, wherein the bases of said first andsecond surface projections are spaced apart from one another along adirection generally transverse to the mid-longitudinal axis of saidimplant.
 215. The orthopedic implant of claim 174, wherein said forwardfacets of each of said first and second surface projections face thesame direction.
 216. The orthopedic implant of claim 174, wherein saidopposed side facets intersect each other.
 217. The orthopedic implant ofclaim 216, wherein said opposed side facets converge to form a peak atthe top of said surface projection.
 218. The orthopedic implant of claim217, wherein said peaks of at least two of said surface projections arealigned along lines that are at least one of perpendicular, parallel,and diagonal to the mid-longitudinal axis of said implant.
 219. Theorthopedic implant of claim 217, wherein said peak of said first surfaceprojection overlies at least a portion of said second surfaceprojection.
 220. The orthopedic implant of claim 217, wherein said peaksof said first and second surface projections are at the same heightabove one of said exterior surface of said implant.
 221. The orthopedicimplant of claim 174, wherein adjacent side facets of adjacent surfaceprojections are spaced apart to define a groove therebetween.
 222. Theorthopedic implant of claim 174, wherein a plurality of adjacent surfaceprojections are spaced apart to form a plurality of groovestherebetween.
 223. The orthopedic implant of claim 222, wherein at leastone of said grooves is parallel to the mid-longitudinal axis of saidimplant.
 224. The orthopedic implant of claim 222, wherein at least twoof said grooves cross each other.
 225. The orthopedic implant of claim222, wherein at least one of said grooves has a horizontalcross-sectional shape that is one of a v-shape, u-shape, and a box-likeshape.
 226. The orthopedic implant of claim 174, wherein said sidefacets have a maximum width therebetween at the bases of said first andsecond surface projections, the bases being spaced apart from oneanother by a distance no greater than one-half the maximum width of oneof said first and second surface projections.